The present invention relates to a ski-boot fastening of the so-called lever-and-ring type, having a device for adjusting the tightness of the fastening.
Until now, the tightness of a ski-boot fastening of the type considered has been achieved in two basic stages: a coarse adjustment by means of the engagement of the ring with an appropriate hook of a plurality of hooks formed or otherwise fixed on a base-plate, and a fine adjustment by means of a screw mechanism usually interposed between the lever and the ring, or an equivalent tightening unit for the ring.
In most ski-boot fastenings currently in use, the fine adjustment may be made directly under load, that is, when the ring is actually subject to the action of the lever or the respective tightening unit.
Now, the fine adjustment stage is usually long and laborious, in view of the fact that the distance (interspacing) between two adjacent hooks on the base-plate is preferably constant for reasons of mechanical strength, which involves the making of hooks of a constant thickness, and the fact that the number of hooks is limited (generally to two or three hooks) particularly for reasons of size (a base-plate of limited dimensions).
In fact, once the ring has been engaged with the particular hook which, out of all the hooks on the base-plate, permits the closure of the fastening with the best possible tightness, the optimum tightness of the fastening is obtained by operating the micrometric screw of the fine adjustment mechanism. The significant amount of time involved in this operation is actually due to the high value of the ratio between the interspacing of the hooks on the base-plate and the pitch of the micrometric screw.